1. Field of the Invention
The present invention relates to an ink supplying system in a liquid ejecting apparatus, and more particularly, it relates to a liquid ejecting apparatus including an ink supplying system capable of detachably connecting and communicating an ink needle to be connected to a tube side so that ink can be supplied from an ink tank to a discharge head portion of a print cartridge via a tube, with an interconnecting member of the print cartridge side.
2. Related Background Art
Image recording apparatuses such as printers, copiers, facsimiles and the like are designed so that an image formed on a recording medium such as paper, a thin plastic plate and the like on the basis of image information, and such image recording apparatuses can be divided into an ink jet type, a wire dot type, a thermal type, a laser beam type and the like. Among them, a liquid ejecting apparatus of ink jet type is designed to effect recording by discharging liquid such as ink from a discharge head (liquid ejecting head) toward the recording medium and has advantages that a highly fine image can be recorded, that it has less noise because of non-impact type and that a color image can easily be recorded by using plural color inks.
In the liquid ejecting apparatus, the image is recorded by the discharge head detachably mounted on a carriage shifted in a scanning direction along the recording medium, and, after one-line recording, predetermined feed of the recording medium is effected (in a sub-scanning direction), and thereafter, an image corresponding to a next line is recorded on the recording medium now stationary, and, by repeating such operations, the recording is effected on the entire recording medium.
Such conventional liquid ejecting apparatuses are grouped into a type in which an ink tank storing the ink therein is mounted on the carriage together with the liquid discharge head and a type in which the ink tank is disposed at an appropriate place different from the carriage and the ink in the ink tank is supplied to the liquid discharge head through a piping (tube).
In the former type, since the ink tank is mounted on the carriage together with the liquid discharge head, the ink supplying system has a relatively simple construction, but capacity (weight) of the ink tank is limited. Particularly, in a printer adaptable to recent photo-images, in many cases, since six color inks are used (ink having low density is added), a tank capacity for each color becomes smaller. Thus, the ink tanks must be replaced or exchanged frequently.
On the other hand, in the latter type, although an ink supplying system for supplying the ink from the ink tank to the liquid discharge head is required and thus the construction of the ink supplying system becomes complicated, since the ink tank can be located at any appropriate place of a main body of the apparatus, there is no problem even when the capacity (weight) of the ink tank is increased, and, thus, this type is inevitable for a large-sized liquid injecting apparatus. Further, cost of ink per unit volume is reduced, and running cost is reduced.
In this way, in the liquid ejecting apparatus of type in which the ink tank is arranged out of the carriage and the ink in the ink tank is supplied to the liquid discharge head through the tube of the ink supplying system, by providing a print cartridge having only one color discharge head and a sub-tank (ink reservoir) and by detachably mounting the print cartridge to the carriage, connection of the ink supplying system is effected.
When the print cartridge is designed for each color, although a mounting force to the carriage is reduced, since a length of each side of the print cartridge is small, it is difficult to enhance positioning accuracy with respect to the carriage, thereby worsening print quality, and, since discrete structures are required for respective colors, a distance between the liquid discharge heads cannot be reduced, and, thus, in order to effect the printing on a predetermined area or range, a shifting range of the carriage must be increased. As a result, a size of the main body of the apparatus is increased and through-put is reduced.
In order to solve such problems, it is preferable that the print cartridge is designed for plural colors. However, in the construction in which the print cartridge is designed for plural colors, joint structures of plural ink supplying systems for supplying inks from the respective color ink tanks to the respective liquid discharge heads of the print cartridge are required, and means for mounting the print cartridge on the carriage and for securing the print cartridge to the carriage and means for connecting the respective joint structures to permit to supply the inks to the secured print cartridge are required. Thus, when the print cartridge is mounted and dismounted with respect to the carriage, the respective joint structures of the ink supplying systems must be retarded greatly not to interfere with the mounting and dismounting of the print cartridge, and, thus, an arrangement for shifting the joint structures becomes bulky and not only arrangement and part for effecting the shifting but also the main body of the apparatus itself becomes bulky.
Further, in a case where such joint structures are included, when the print cartridge is mounted and dismounted with respect to the carriage, the ink in the joint portions may be scattered into the interior and/or exterior of the apparatus, thereby contaminating the usage environment and reducing the reliability of the main body of the apparatus.
The present invention is made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a liquid ejecting apparatus having an ink supplying system for supplying ink from an ink tank to a print cartridge detachably mounted on a carriage through a tube, in which connection and communication between an ink needle connected to a tube side and an interconnecting member of a print cartridge side can be sealingly effected positively with high accuracy and ink supplying and connecting means can be made small-sized and a main body of the apparatus can also be made compact.
To achieve the above object, the present invention provides a liquid ejecting apparatus wherein a print cartridge having a discharge head portion for discharging a liquid droplet is detachably mounted on a carriage, and the apparatus comprises an ink supplying and connecting mechanism for detachably connecting and communicating an ink needle connected to a tube side and an interconnecting member of a print cartridge side in order that ink can be supplied from an ink tank to the print cartridge through a tube, and further wherein the print cartridge comprises the discharge head portion for discharging the liquid droplet in response to a received electrical signal, a sub-tank for temporarily storing the ink to be supplied to the discharge head portion and a cartridge body portion for forming an ink flow path for connecting the sub-tank to the discharge head portion, and an ink flow-in member having a cylindrical projection portion into which the interconnecting member formed from soft material for receiving the ink from the ink tank is fitted by inserting the ink needle connected to the tube side, and a closing film having a small hole and a slit is formed at an ink needle inserting tip end of the interconnecting member.
In the liquid ejecting apparatus of the present invention, the small hole of the interconnecting member preferably has an inner diameter smaller than an outer diameter of the ink needle, and it is preferable that a length of the small hole of the interconnecting member in an ink needle inserting direction is equal to or greater than 1 mm and a thickness of the closing film is equal to or greater than 0.2 mm and equal to or smaller than 1 mm. Further, an ink needle inserting tip end of the small hole of the interconnecting member is preferable tapered.
In the liquid ejecting apparatus of the present invention, it is preferable that a needle tip end avoiding configuration is provided at a tip end of the cylindrical projection portion of the ink flow-in member, and it is also preferable that the ink flow-in member has a flat plate-shaped portion joined to the cartridge body portion to form the ink flow path to the sub-tank and the flat plate-shaped portion is joined to the cartridge body portion by vibration welding.
In the liquid ejecting apparatus of the present invention, it is preferable that the ink needle is held by a needle holding member shiftably provided on the carriage so that the ink needle can be insertion-connected to and detached from the interconnecting member of the print cartridge, and it is also preferable that the needle holding member is shifted toward and away from the print cartridge by a needle shafting lever rotatably supported on the carriage.
In the liquid ejecting apparatus of the present invention, it is preferable that the ink flow-in member is provided with a plurality of interconnecting members and a plurality of ink needles are provided in correspondence to the respective interconnecting members.
In the liquid ejecting apparatus of the present invention, it is preferable that, when the ink needles are inserted into and connected to the interconnecting members of the print cartridge, the ink needles penetrate into the slits of the closing films in a condition that the ink needles are sealed by the small holes of the interconnecting members.
In the liquid ejecting apparatus of the present invention, it is preferable that, when the ink needles are dismounted from the interconnecting members of the print cartridge, the ink needles are passed through the slits of the closing films in a condition that the ink needles are sealed by the small holes of the interconnecting members.
According to the present invention, by fitting the cylindrical interconnecting member made of rubber or soft resin and including the closing film having, at its tip end, the small hole and the slit for receiving the ink needle into the cylindrical projection portion constituting the ink flow-in member provided on the print cartridge and by vibration-welding (ultrasonic welding and the like) the ink flow-in member to the print cartridge body, connecting means of the ink supplying system can be manufactured with a simple construction, and, by forming the closing film having the slit and small hole having the inner diameter smaller than the outer diameter of the ink needle on the interconnecting member, when the ink needle is inserted, the sealing can be maintained by face contact between an outer surface of the ink needle and an inner surface of the small hole, and, when the ink needle is detached, flow-out of the ink in the print cartridge and entering of dirt from outside can be prevented. In this way, with a simple construction, communication of the ink supplying system by connection between the interconnecting member and the ink needle can be achieved sealingly and positively with high accuracy. Further, in this case, since the ink needles are inserted into and retracted from the slits of the closing films in the condition that the ink needles are sealed by the small holes of the interconnecting members, the ink is not scattered into the interior and/or exterior of the apparatus.
Further, by providing the notched ink needle tip end avoiding configuration for avoiding contact between the tip end of the ink needle and the ink flow-in member at the tip end of the cylindrical projection portion of the ink flow-in member in the print cartridge, a shifting amount of the needle holding member which was required when the print cartridge is mounted and dismounted can be reduced, and the structure for shifting the needle holding member and the printer body can be made compact.